Various types of illumination devices are generally well known in the art. Self-contained illumination devices, such as flashlights, portable lamps, decorative lights, and the like employ the use of a light source powered by a replaceable power source, such as disposable or rechargeable batteries. For example, U.S. Pat. No. 4,835,665 to Kao discloses an emergency flashlight that has a traditional flashlight housing containing a continuously burning bulb and a battery power source for providing continuous, directed light, as well as a separate housing (detection box) containing a flashing user lamp and a battery power source for producing intermittent bursts of light. Often, such devices employ incandescent bulbs, which typically include a coiled tungsten wire filament disposed in a glass casing, which is usually filled with an inert gas such as krypton, halogen, or xenon. The ends of the wire filament are connected to the ends of corresponding wires that supply electrical current, which, in turn, are usually connected to terminals in the base of the bulb that facilitate connection to a source of electrical power, such as a battery. As current flows through the wire filament, it heats to a very high temperature and gives off visible light. There are, however numerous disadvantages to such devices, including, among other things, that the intensity of the light is limited and the radiation of the light is directional, resulting in a limited degree of illumination, for a limited spatial area, at any particular point in time. Additionally, the device, as well as the power sources required to power the device, are usually cumbersome, easily broken, and somewhat expensive to manufacture.
It has been suggested to use light emitting diodes in portable illumination devices, such as in the device disclosed in U.S. Pat. No. 6,511,214 to Parsons et al. However, similar problems still result, as these diodes emit light in a relatively directional manner, thereby limiting the amount of area that can be illuminated at any one time. Similarly, because any attempts to maximize the intensity of the light emitted by the diodes will result in excessive consumption of power, weak diodes must be used, or the current supplied to the diodes must be substantially restricted, whenever a self-contained illumination device is involved, as the portable power source will quickly be expended.
What is desired, therefore, is a device that can illuminate a very large area at once. What is further desired is a device that can produce very high intensity light for extended periods of time. What is also desired is a device that is not cumbersome, easily broken, or expensive to manufacture.